Expansion and contraction switch



June 3, 1930. H. s. SCHLICHTER 1,761,455

EXPANSION AND CONTRACTION SWITCH Filed March 5, 1928 Patented June 3, 1930 HENRY GERHARD SCHLICHTER, OF FITCI-IBURG, MASSACHUSETTS EXPANSION AND CONTRACTION SWITCH Application filed March 5, 1928. Serial No. 259,261.

The object of this invention is to provide a switch which is operable by movements of a thermostatic abutment to quickly close and break an electric circuit, the abutment being a free or unattached end of a rod of material adapted to be expanded by heat and contracted by cooling, and fixed at its opposite end so that the free end is adapted to have a limited forward and backward movement in predetermined directions.

Of the accompanying drawings forming a part of this specification- Figure 1 is a side view showing a switch embodying the invention, conditioned to close 1 an electric circuit.

Figure 2 is an edge view of the same, the holder being shown in section taken on the line 22 of Figure 1.

Figure 3 is a view similar to Figure 1, showing the switch conditioned to break the cireuit.

Figures 1, 2 and 3 show in section the fixed holder or support of the switch, and Figures 1 and 3 show a thermostatic rod.

Figure 4 is afragmentary view, showing a portion of the holder and the primary lever shown by the preceding figures.

Figures 5 and 6 are perspective views respectively, of the intermediate and outer levers hereinafter described.

The same reference characters indicate the same parts in all of the figures.

A primary lever composed of a longer arm 12, and a shorter arm 13, is adapted to oscillate on a fulcrum stud 14, secured to a fixed holder 15. The primary lever is, in this instance, a flat-sided oblong plate, wider at one end than at the other, the wider end portion constituting'the shorter arm and having an,

40 end face 13, adaptedto bear on a thermostatic abutment 16, which may be an end of a rod 16 of material adapted to be expanded and contracted by changes of temperature, the rod being fixed at its opposite end so that its expansion and contraction move the abutment 16 in predetermined directions, the abutment and the biasing spring hereinafter described being adapted'to move the primary lever to the positions indicated by Figures 1 and 3.

dotted lines in Figure 1.

A biasing spring 17 secured at one end to a fixed member 18, and at the opposite end to the longer arm 12, holds the end face 13 in yieldingcontact with the abutment 16, so that when the rod 16 is contracted by cooling, the primary lever is in the position shown by Figure 1, and by full lines in Figure 4, and when the rod is expanded by heat, said lever is in the position shown by Figure 3, and by A tilting circuit controller which includes a guide 19, preferably a glass tube closed at its ends, and a sleeve 20, through which the tube extends, is tiltable by the described movements of the primary lever, and the connecting means hereinafter described between the controller and the primary lever, to incline the tube, as shown by Figure 1, when the rod 16 is contracted, and as shown by Figure 4, when the rod is expanded, the sleeve 20 being adapted to turn or rock on a pivot 21 (Figure 2) fixed, in this instance, to a stud 22 (Figure 4) on the holder 15.

In one end of the tube 19 are two electrodes 23, spaced apart and insulated from each other, and connected with circuit wires 24 included in an electric circuit. Movable by gravity in the tube 19 is a circuit closing and breaking element 25, which is preferably a body of liquid mercury. When the tube is in the position shown, by Figure 1, said element electrically connects the electrodes 23, and when the tube is in the position shown by Figure 3, the electrodes are disconnected.

It will be seen by reference to Figure 4, that the amplitude of the movements of the primary lever is very limited. To enable said limited movements to tilt the circuit controller as shown, I provide connecting means next described, said means including a series of compounded levers.

27 designates a crank arm fixed to the sleeve 20, and provided with a wrist-pin 28 projecting into a slot, preferably formed by spaced apart fingers 29, on one end of an outer 95 lever 30, which is pivoted at its lower end portion to the longer arm 12 of the primary lever, preferably by a pivot screw 33 (Figure 2) inserted in an orifice 31 (Figure 6) in the lever 30, and engaged with a stud 34 (Figure 4) fixed to said longer arm. The lower end portion of the lever 30 is here shown as U-shaped. but this form is not essential.

Formed in the lever 30 and spaced from the orifice 31 is a slot 32, which is loosely entered by a stud 42 on the lower end of an interlnediate lever 35 (Figure 5). The upper end portion of the intermediate lever 35 is pivotally connected with the shorter arm 13 of the primary lever, preferably by a stud 41 on said shorter arm, said stud entering a slot 40 in the intermediate lever. Said intermediate lever is pivotally connected with thQfiXGd holder 15, preferably by the pivot screw 21, which connects the sleeve 20 of the circuit controller with the fixed st'ud 22, the intermediate lever 35 having an orifice 36 receiving the pivot screw 21.

WVhen the rod 16 is contracted, the primary lever, the outer lever 30, and the intermediate lever 35 assume the relative positions shown by Figure 1, and the tube 19 of the circuit controller is inclined by the outer lever 30 and the crank 27, to cause the movable element 25 to close the circuit.

When the rod is expanded, said levers assume the relative positions shown by Figure 3, and the tube 19 is inclined by the outer lei er 30 and the crank 27, to cause the said movable element to break the circuit.

The described movements of the primary lever are multiplied by the intermediate lever 35, so that the outer lever 30 has a sufficient amplitude of swinging movement on the fulcrum provided by the stud 42, to tilt the tube 19 to the different positions shown,-the intermediate lever 35 being oscillatable in a limited arc by movements of the primary lever, while the outer lever 30 engaged with the crank, is oscillatable in a longer arc.

To limit the tilting movements of the guide 19 in each direction, I provide the intermediate lever 35 with a stop pin 37, and the sleeve 20 with stop ears 38, said pin and ears cooperating as indicated by Figures 1 and 3. The ears 38 are preferably rendered adjustable by screws 39.

It will be seen that the described switch is operable by a limited movement of the ther mostatic abutment 16, to close and break an electric circuit for a useful purpose.

I claim:

1. A switch comprising, in combination, a thermostatic abutment movable in a predetermined path by expansion and contraction, a holder fixed relative to the abutment, a circuit controller pivotally connected with the holder, said controller including a tiltable guidehaving spaced apart electrodes insulated from each other, and a circuit closing and breaking element, a series of compounded levers including a biased primary lever fulcrumed on the holder and having a shorter arm maintained in yielding contact with the abutment and a longer arm, an outer lever HENRY GERHARD SCHLIOHTER. 

